Saw blades, such as saw blades for sawing lumber or other wood materials, generally are formed utilizing a multi-step manufacturing process. In the context of bandsaw blades, this manufacturing process may include laying out a strip of metal, which will be formed into the bandsaw blade, and forming and/or defining a plurality of rough-cut saw teeth within the strip of metal. Subsequently, the ends of the strip of metal are welded together, or otherwise joined, to form and/or define a band, and the band is tensioned across a width thereof.
Whether the blade is a bandsaw blade or a circular saw blade, the rough-cut saw teeth may be roughly defined within the saw blade utilizing any suitable process, such as laser cutting, water jet cutting, and/or punching. In the case of laser cutting, the cutting process heats the saw blade, and the resultant rough-cut saw teeth include a heat-affected zone, which may be several thousandths of an inch thick. This heat-affected zone is harder than a remainder of the saw blade, and the presence of the heat-affected zone may be detrimental to the longevity of the saw blade. As an example, a gullet of the saw blade may crack if the heat-affected zone is not removed.
In addition, the rough-cut saw teeth may vary in height. This height variation may be on the order of several tens of thousandths of an inch and may be detrimental to the performance and/or longevity of the saw blade.
Subsequently, a final, finished, and/or desired tooth profile is formed and/or defined within the saw blade. The operation that is utilized to form the finished tooth profile also may be utilized to remove the heat-affected zone and/or to decrease the height variation among the teeth. After formation of the finished tooth profile, a cutting edge, or tip, may be swaged into each tooth and/or brazed, or welded, onto each tooth.
Generally, removal of the heat-affected zone, decreasing the height variation, and definition of the finished tooth profile are performed concurrently via a grinding operation. This grinding operation may be a multiple-pass dry-grinding operation in which a few (generally 3-5) thousandths of an inch (0.076-0.127 millimeters) of metal is removed during each of several dry-grinding passes. The dry-grinding passes progressively remove the heat-affected zone while, at the same time, progressively changing the shape of the teeth until the finished tooth profile is obtained.
While grinding operations may be effective under certain circumstances, they have distinct limitations. As an example, the process of grinding the saw blade also can heat the saw blade. Thus, care must be taken to ensure that the grinding operation progresses slowly enough, or is sufficiently cooled, to avoid heating the saw blade above a critical temperature at which formation of a new heat-affected zone occurs. As another example, and as discussed, dry-grinding operations generally require a number of passes, causing the dry-grinding operation to be the most, or one of the most, costly and time-consuming steps in the manufacture of a saw blade.
As yet another example, a wet-grinding operation may be utilized to define the finished tooth profile. Such wet-grinding operations utilize a liquid coolant to cool the saw blade, thereby permitting the finished tooth profile to be defined in fewer passes than generally are required for dry grinding operations. However, wet-grinding operations require frequent dressing of the grinding wheel, which significantly increases the time required to perform the wet-grinding operation. In addition, wet-grinding operations also represent an environmental hazard in the context of liquid coolant disposal. Furthermore, wet-grinding operations that utilize a hydrocarbon coolant may pose a fire hazard and may require explosion and/or fire suppression systems, further increasing the cost and/or complexity of such operations.
As another example, a grinding wheel that is utilized during the grinding operation exhibits a significant amount of wear and must be re-dressed several times during the grinding of a single saw blade, adding to the time and cost of grinding the saw blade. As yet another example, it may be challenging to maintain a desired level of tooth tip height uniformity when defining saw teeth with the grinding operation. As another example, the tooth profiles that may be defined by the grinding operation are limited due to the large diameter of the grinding wheel. As yet another example, and in the case of the wet-grinding operation, a coolant that is utilized during the wet-grinding operation may pose an environmental disposal hazard. Thus, there exists a need for improved systems and methods for manufacturing saw blades.